Input–Output Logic of ODES WY-35A4 Three-Phase Voltage Supervision Relay
- TonyZhang
- Sep 27
- 2 min read
In engineering practice, different systems may require different alarm and reset logics for three-phase undervoltage supervision relays. To align design, commissioning, and operations, ODES offers two typical logic strategies within the WY-35A4 series:
Standard Logic (WY-35A4)
Customized Logic (WY-35A4-T)
Understanding their differences helps engineers select the right model and validate performance in the field.
Standard Logic: WY-35A4
Pickup logic: If any one phase voltage drops below the set threshold, the relay starts timing (default 0 ms, adjustable). When the delay expires, the relay contact changes state and outputs a signal.
Reset logic: Contacts return to the initial state once all three phases exceed the reset value (typically 1.1 × pickup setting).
Typical applications:
PT voltage supervision.
Metering voltage supervision.
Customized Logic: WY-35A4-T
Pickup logic: Timing starts only when all three phases drop below the threshold (default 0 ms, adjustable). When the delay expires, the relay contact changes state and outputs a signal.
Reset logic: Contacts return to the initial state when any one phase exceeds the reset value (typically 1.1 × pickup setting).
Typical applications:
Grounding switch blocking circuits, ensuring circuits are fully de-energized before closing grounding switches for maintenance.
Rail transit and other systems requiring strict blocking logic.
Engineering Value
By offering both standard undervoltage logic and customized blocking logic, ODES WY-35A4 relays give engineers flexibility to design according to project needs—whether for conventional PT supervision or safety-critical interlocking circuits.
Choosing the right undervoltage relay logic can make the difference between a nuisance alarm and a safe interlock. If your project requires guidance on PT supervision or blocking logic design, our engineers are ready to support.
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